Fire fot block



F. R. HIGLEY I FIRE POT BLOCK Dec. 19, 1944.

INVENTOR. fi'A/Y/K E 14/54 5? 44 4 8 2 F 4 J m 4 M w .ww V ma 1 F Two blocks of each of two different'courses are illustrated in Fig. 7 in assembled relation. It will be noted that the blocks of one course are staggered with respect to those of the next course.

Thereby the central part of the overhang of each block stands directly above the joint between two blocks of the course next beneath. This is of some importance inasmuch as the joints may not fit perfectly in all cases, and if they were not staggered but were in vertical alignment some leakage of pulverulent material might occur through a jointinto the cavity below the overhang. In other words there might be occasional stoppage of the passage at the jointsbetween blocks. I

It may -'be noted also that since the flat rear surface 31 of a given block overlaps the similar surfaces of the blocks next above and below, a series of small vertical passages 4i between the lining and the shel1 l2 are provided, extending from top to bottom of the fire pot.

In Fig. 6 I have indicatedby the broken line 42 the angle of repose considered radially of pulverulent material in the fire pot. Directly beneath the strip 35' constituting the middle part of the overhang a cavity 43 results which is open for the passage of air and/or unburnt gases and products of combustion. The blocks beneath the overhang constitute the inner wall of this cavity,

but it continues up along both sides of the over- I hang between the surfaces 31 and triangular surfaces 44. These cavities continue in decreasing cross-section toward the upper and outer corners of the triangular surfaces 31 and 44. Considerably before a given cavity to one side of an overhang runs out, however, it. communicates with a cavity formed by an overhang of a block in the course next above, so that a substantially continuous passageis provided from one cavity to the next. These passages are inclined and they may .be considered to define helical paths from the bottom to the top of the fire pot. There are two sets of such helical paths inclinedin o site directions, providing both right-hand and lefthand threads. These crossed passages define in addition zigzag paths from the bottom to the top of the fire pot, and it is'these zigzag paths which are ordinarily utilized primarily, I believe, as draft passages for the air and gases.

Considered with respect to the radial distance from the shell l2, the single high point of this block isthe small triangular surface 40. There are four low points marked L in the drawing, and three intermediate points marked I. All of the low points are positioned at the same radial distanc from the axis of the fire pot and all of the intermediate points have another like dimension. When the blocks are assembled into with the low points at the adjacent ends of the two blocks next beneath. The blocks are so designed also that the intermediate points I of a given block are in the same plane with the triangular high spot 46, this plane being parallel to the plane of the surface 3'! at the back of the block. This is of some importance because it reduces to a minimum the Voids in the block, and thereby gives maximum strength and reduced die cost. The location of the intermediate points at the ends of the block in the same plane with the high spot 40 also facilitates packaging of the block.

The location of the high spot 40 and the ridge "38 at the middle of the block is of advantage because it places the maximum thickness dimen-. sion at the middle where the strain is greatest. When coking occurs and causes expansion in the fuel bed, heavy pressures are exerted radially outward on the various blocks. The maximum thickness dimension at the center therefore assists the block to withstand this strain.

The die which is employed for molding the front face of the block must, of course, be withdrawn by movement in a direction normal to the back surface ill. The triangular surfaces 31 are parallel to this direction of movement except for the minimum necessary draft, but with respect to axial planes, in which the pulverulent material a lining, intermediate points at the adjacent ends flows primarily, the surfaces 31 incline upwardly to an increasing extent toward the outer extremities of those surfaces, thereby increasing the cross-sectional area of the cavities or passages toward their outer ends over what those areas would be if the intersections of the surface 31 with all axial planes remained horizontal lines. This condition will be apparent from an inspection of Fig. 5, where the cavity is marked 43.

The block herein disclosed may be used in either an up draft or a down draft furnace, it being essential merely that the draft passages extend throughout the length of the fire pot from bottom to top thereof.

Having thus described my invention, I claim:

1. A block for building up the lining of a fire pot, having front and back walls, top and bottom walls and two side walls, said front wall having a high spot overhang at the. lower end of its midsection and having low spots at its upper corners and spots of the same intermediate height at its lower corners and the upper end of its mid-section, whereby when a series of blocks are assembled in staggered relation the low spots come under the overhangs and the points of intermediate height come together, forming a pattern of substantially diamond shaped areas with their high spots at the bottom corners and low spots at the other three corners.

2. A refractory block for use in building up the lining of a cylindrical fire pot, said block having side walls conforming with radial planes through the axis of the fire pot, an overhang at the lower end of the mid-section of the front face of the block, the side surfaces of said overhang diverging upwardly toward the side walls of the block and lying in planes substantially perpendicular to the vertical plane through the chord of the arc subtended by the block, whereby radial planes to either side of the median axial plane will define undercuts beneath said overhang.

FRANK R. HIGLEY. 

